Prevalence of C-Reactive Protein Elevation and Time Course of Normalization in Acute Pericarditis: Implications for the Diagnosis, Therapy, and Prognosis of Pericarditis

Background— The role of inflammatory markers is not well defined for either diagnosis or treatment of pericarditis. The aim of this study is to prospectively evaluate the frequency of high-sensitivity C-reactive protein (hs-CRP) elevation in patients with acute pericarditis, its time course of normalization, and the possible importance for diagnosis, therapy, and prognosis. Methods and Results— Two hundred consecutive patients with viral or idiopathic acute pericarditis (mean age, 53±15.5 years; 103 men) were studied from August 2005 to August 2007 in 2 Italian referral centers. Hs-CRP was determined at presentation and then every week until normalization. Hs-CRP elevation was recorded in 156 of 200 cases (78%) at presentation. Recognized causes of a negative hs-CRP at presentation were early assessment in 15 of 44 cases (34%) and previous anti-inflammatory therapies in 22 of 44 cases (50%). Hs-CRP normalization was achieved with the following time course: 120 of 200 (60%) at week 1, 170 of 200 (85%) at week 2, 190 of 200 (95%) at week 3, and all cases (100%) at week 4. In multivariable analysis, incomplete response to empirical anti-inflammatory therapy at week 1 (hazard ratio, 2.98; 95% confidence interval, 1.80 to 4.94; P<0.001), corticosteroid therapy (hazard ratio, 2.80; 95% confidence interval, 1.59 to 4.95; P<0.001), and the presence of elevated hs-CRP at week 1 (hazard ratio, 2.36; 95% confidence interval, 1.32 to 4.21; P=0.004) were independent risk factors for recurrence. Conclusions— Hs-CRP is elevated at the initial presentation in ≈3 of 4 cases of acute pericarditis, identifies patients at higher risk of recurrence, and could be used to monitor disease activity and select appropriate therapy length.